A hybrid inflator for inflating a vehicle occupant protection device includes a quantity of a stored gas and a body of combustible material. The stored gas typically comprises an inert gas and an oxidizer gas. The oxidizer gas helps to support the combustion of the body of combustible material. An igniter is actuatable to ignite the body of combustible material. As the body of combustible material burns, combustion products heat the inert gas. This increases the pressure of the inert gas. The heated inert gas and the combustion products form the inflation fluid.